public class test {
    public static int fib(int n){
        int f1=1;
        int f2=1;
        int f3=0;
        for(int i=3;i<=n;i++){
            f3=f1+f2;
            f1=f2;
            f2=f3;
        }
        return f3;
    }

    public static void main(String[] args) {
        System.out.println(fib(40));
    }
}
